To control structure vibration effectively, an effective passive vibration isolation device based on the theory of negative stiffness is presented. The device can improve system capacity and reduce the inherent stiffness of system and isolate low-frequency vibration effectively through paralleling positive and negative stiffness substructures. Through the analysis of the structure and stiffness characteristics of the device, set up the equipment of the stiffness function expression and the zero stiffness of equilibrium position condition, then find the influence of main parameters and its optimization. Using MADIS finite element software, the vibration reduction effect of the frame structure under earthquake load is analyzed, and compared with the original framework, research shows that the device can effectively control the structure vibration, and parameter optimization result is valid. The study results provide theoretical basis for subsequent experimental study and practical application of the device.